Telephone-exchange apparatus and system



J. ER|CKSON-, TELEPHONE EXCHANGE APPARATUS AND SYSTEM. APPLICATION FILEDJULYIQ, mos. RENEWED 1 N.2,191a.

Patented Aug. 6, 1918-.

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TELEPHONE EXCHANGE APPARATUS AND SYSTEM. APPLICATION FIL ED JULYI9|I906. RENEWED JAN. 2. i918. 1 ,2?5,142, Patented Aug. 6, 191-8.

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JOHN EBICKSON', OF CHICAGO, ILLINOIS, ASSIGNOR, BY'MESNE ASSIGNMENTS, TOAUTOMATIC ELECTRIC CO., A CORPORATION OF ILLINOIS.

TELEPHONE-EXCHANGE APPARATUS AND SYSTEM.

Specification of Letters Patent.

Application filed July 19, 1906, Serial No. 326,931, Renewed January 2,1918. Serial No. 210,071.

To all whom it may concern.-

Be it-known that I, JOHN ERIoKsoN, a citizen of the United States ofAmerica, and resident of Chicago, Cook county, Illinois, have invented acertain new and useful Improvement in Telephone-Exchange Apparatus andSystems, of which thefollowing is a specification.

My invention relates to automatic or semiautomatic telephone systems,and more especially to automatic telephone exchange systems in whichelectrically-propelled and step-by-step-actuated switching machines areemployed at the exchange or central station, together with suitablecalling devices at the subscribers stations for controlling the saidswitching machines, whereby the calling subscriber may, by using hiscalling device for transmitting electrical impulses over his telephoneline, automatically extend connection from his telephone line to theline of the called subscriber, and in which provision is made for thenautomatically producing an audible call-signal at the station of thecalled subscriber, as well as for automatically disconnecting andrestoring the switching machinery after the subscribers are throughtalking, all without the assistance of operators at the exchange orcentral station.

For example, my invention is applicable to automatic telephone exchangesystems of that particular character in which selectors are employed fortrunking from the calling telephone line to a group of automaticconnector-switches, which automatic connector switches are employed forestablishing the final connection directly with the called subscriberslines, each connector being adapted to respond to the electricalimpulses representing the last two digits of any called number, and theselectors being adapted to respond to all other electrical impulsesrepresenting the ,other digits of any called number, it being usual toprovide as many different classes of selectors as there are digits inaddition to the last two of any called number, as, for example, andassuming that. each called number contains four digits, there will befirst selectors for making trunking connections in accordance with thefirst digit of any called number, and second-selectors for establishingtrunking connections in accordance with the second digit of any callednumber, each second-selector being adapted to automatically pick out orselect a non-busy connector, which latter will ,then make the finalconnection in accordance with the last two digits of the called number,providing, of course, that the called line is not busy, for

Patented Aug. 6, 1918,

should this be the case the connector will then refuse to establishconnection with the called line, and a busy signal will be transmittedto the calling subscriber.

My invention is an improvement on the apparatus and system of myco-pending aplication Serial No. 326,450, filed July 16, 1906. In thepresent application the claims are limited to a repeater which controlsa circuit separate from the talking circuit for releasing. In said priorapplication the repeater therein disclosed operates in conjunction withbridging selectors-that is to say, selectors having line relays whichare allowed to remain bridged across the talking circuit duringconversation, for the purpose. of permitting these relays to be used inreleasing the switches after the subscribers are'through talking. Inthis application, however, I have disclosed and claimed a repeaterhaving provisions for closing a trunk release circuit back over a thirdtrunk conductor, in the direction of the calling subscriber, and throughthe firstselector or other automatic switch, thus making it possible tocombine a repeater with selectors or other switches having line relayswhich can be cut off from the talking circuit. during conversation.

Generally stated the object of my present invention is the provision ofan improved construction and arrangement for permitting the cutting offof the bridged line relays of automatic switches in a system in whichrepeaters are employed for repeating or relaying switch operatingelectrical im-' making it ossible to leave the line relays of onlythe-repeater and the connector bridged across the talking circuit duringconversation between the subscribers. Special objects of my presentinvention are the provision of a repeater having a relay provided withnormally open switch contacts included in a trunk release circuitextending back over a third trunk conductor to a selector or otherautomatic switch included in the circuit between the repeater and thecalling subscribers line, whereby the energizing of said relay willrelease or restore the said selector or other switch; the provision of arepeater having a relay provided not only with the said normally openswitch contacts for closing the trunk release circuit, but also withmeans for mechanically releasing the line wipers or other circuitclosing devices of the said repeater, whereby the energizing of saidrelay not only releases and restores the said selector or other switchincluded in the circuit between the repeater and the calling subscribersline, but also efi'ects a release or restoration of the repeater itself;and the provision of certain details and features of" improvement andcombinations tending to increase the general efliciency andserviceability of an automatic telephone exchange system of thisparticular character.

To the foregoing and other useful ends, my invention consists in mattershereinafter set forth and claimed.

In the accompanying drawings, Figure 1 is a diagram showing asubscribers line connecting the substation A #6000) with its allottedfirst-selector B, and with the repeater C.

Fig. 2 shows in diagram a called substation D (#2220), a first-selector.E allottedto the called line, a connector-switch F, and asecond-selector G.

Fig. 1 represents theapparatus at the central exchange or oihce #1, andFig. 2 represents the apparatus at a second central oflice which will bedesignated as #2.

Figs. 1 and 2 taken together show a system embodying the principles ofmy invenshown in an operative condition, maintaining the connectionbetween the two sub-.

stations. Each exchange or central ofiice has its own battery, thecentral ofice; #1

able voltage, but good results are obtained when they are built to givea pressure of from 50 to 55 volts.

The substation shown in Fig. 1 is, as

sible to rotate the dial.

tion and represent a temporarily established connection between thesubscribers A and D. a

It will be-noticed that the apparatus is usual, provided with a receiver2, transmitter 3, ringer 4, induction-coil 5, switch-hook 6, impulsewheel 7, cam latch 8 (fornormally locking the dial), a cam dog 9, and a.battery 10'. The impulse wheel 7 is, of course, provided with a set ofvertical impulse teeth 11 and a rotary impulse tooth 12 for operating,respectively, the vertical impulse linger 14: and the rotary impulsefinger 18 with respect to the ground post 15. The substation ground G ispermanently connected to the ground spring, 16, which latter is normallyheld away from the ground spring by the insulating tip 18 upon the endof the cam latch 8. Said insulating tip normally rests opposite theangled terminal of the ground spring 16, as shown at substation D Fig.2. it will be understood, of course, that in the subscribers dial (whichis not shown, but which may be of any suitable or approved type), theimpulse wheel 7 and the cam dog 9 are all rigidly secured to the shaft19. JVhile the receiver is on the switch-hook the switch-hook cam arm 20removes the ground spring 16 from the insulating tip 18 so that the camlatch 8 falls in front of the pin 21, on the end of the cam dog 9, sothat it becomes impos- VVhen the receiver is removed, however, theswitch-hook is raised by a suitable spring (not shown), and the cam arm20 by engaging the face 22 of the cam latch 8 raises the lattersu-fiiciently to permit the pin 21 to pass under the cam latch when thedial is sufficiently rotated.

It will be understood, however, that the ground spring 16, when the camarm 20 leaves its normal position, falls against. the insulating tip 18and remains there, and out of engagement with the other ground spring17, until the dial is rotated, since the cam arm 20 does not raise thecam latch 8 sufficiently to permit the tip 18 to clear the angledsection on the end of the ground spring 16. The extreme end of the camlatch 8, which is engaged by the'cam dog pin 21, is not angled butrounded 03 in such a'man- .ne-r that when the dial is rotated the pin 21slides beneath the said rounded section and raises the cam latch 8 atrifle more, so that the insulating tip 18 may now leave the groundspring 16, permitting the latter to engage the ground spring 17 and thusestablish connection-between ground G and the ground post 15. When thereceiver is on the hook the cam 23 on the latter engages the spring 24and thereby closes the ringer across the line. lBy depressing the springthe said cam arm not only closes the substation ringing circult, but byseparating I,

the s rings 25-and 26 opens the local. circuit, and y separatlng thesprings 27 and 28 opens the secondary circuit for. removing the receiver2 from'across the line. When the switch-hook is up, the primary circuitLaramie is closed, the ringer is ofi the line, and the secondary circuitcomprising the receiver 2 is bridged across the line. However, while thedial is being operated and, therefore, while the cam 29 of the cam dog 9is out of normal position, the secondary circuit is opened up at thepoint between the springs 27 and 28, so that no electric; impulses thatmay bedelivered to either of the subscribers line conductorsindividually shall pass through the receiver to the other side of thecal side of the subscribers line may be' grounded when he signals. Withthis apparatus, the subscriber when he wishes to make a call removes hisreceiver from the switch-hook and thereby disconnects the ringer fromacross the line, closes his local talking circuit and connects hissecondary circuit across the line.- He then operates his dial once foreach digit of the number he is'to call. At the operation of the dial forthe first digit connection is made between the substation ground G andthe ground post 15, and the secondary circuit is opened between thesprings 27 and 28 at the forward motion of the dial. At the re-" turnmotion of the dial the subscribers vertical line conductor is grounded anumber of times equal to the numerical value of the first digit, andthen the rotary side of the line is grounded .once, and then thesecondary circuit is again' closed between the springs 27 and 28. At thesecond operation of the dial the secondary circuit is again opened atthe same point at the forward motion of the dial, and at thereturnmotion of the dial the vertical line conductor is grounded a number oftimes equal to the numerical value of the second digit, then the rotaryside of the line is grounded once and then the secondary circuit isagain closed. Each succeeding operation of the dial accomplishes thesame result accomplished by the second operation of the dial. The numberhaving been called the signaling button 34 is pressed, whereby thesecondary circuit is opened between the spring 35 and contact point 36,and the vertical side of the line is grounded when the spring 35 engagesthe contact point 37. If the called subscriber is not busy,the pressingof the signaling button rings the called subscribers substation bell;but if he is busy a busy signal will be sent back to the callingsubscriber. When a subscriber is through, by. hanging up his receiver hepressesthe release-springs 31, 32 and 33 into contact for a moment,grounds the subscribers line conductors simultaneously for a moment, andthus restores all the switching apparatus that has been broughtintoservice by him.

The first-selector may be of any suitable or approved type, scribed inPatent No. 815,321. Normally the subscribers vertical and rotary lineconductors 38 and 39 terminate, respectively, in the vertical and rotaryline relays 40 and 41. Theconnection is maintained through the sideswitch wipers 42 and 43, respectively, the former being normally inengagement with the contact point 44, and the latter with the contactpoint 45.. The side switch, as is well known, comprises besides the sideswitch wipers 42 and 43 the private side switch wiper 46 and the rotarymagnet side switch wiper 47. The side switch is controlled by theprivatemagnet 48, and in the normal or first position of the side switchthe side switch wipers 42, 43, 46 and 47 engage, respectively, with thecontact points 44, 45, 49 and 58; in the second position they rest onthe contact points 51, 52, 53 and 54, respectively; and in the thirdposition in engagement with the contact points 55, 56, 57 and 50,respectively, Through the medium of the vertical line relay 40, whilethe side switch is in first or second position, the subscriber controlsthe vertical magnet 59, which latter operates vertically theswitch-shaft (not shown) that carries the line" wipers 60 and 61 and theprivate wiper 62. Through the medium of the rotary line relay 41, whilethe side switch such as the selector deis in first or second position,the subscriber controls the private magnet 48 and, therefore, the sideswitch. When the side switch is in second position the rotary magnet 63is energized and the switch-shaft that carries the wipers 60, 61 and 62is operated. in a rotary direction. The vertical and rotary line relays40 and 41 provide the means by which the release-magnet 64 is controlledby the subscriberwhile the side switch is in first or second position.If the side switch when the shaft is in normal position, presses thespring 66 onto the contact point 67 and thereby makes a connectionbetween the bridge-cut-off-relay 68 and the private nor.- mal conductor69' that leads to the connector private bank, and by way of said privatenormal conductor the bridge-cut'-ofi'-relay 68 is energized whenever anysubscriber calls the substation A. The said bridge-cut-Oif relaycontrols the connection between the vertical and rotary line relays 40and 41 and the battery B It is necessary to thus disconnect said relaysfrom battery, because if not the ringing current finds a path throughthe said relays, thus causing some danger from interference. Also, it isdesirable to remove the bridge from across the line that is formedthrough the line re lays 10 and 41 in series. lVhenever theselector-switch B is operated, however, the spring (30 engages thegrounded contact point just above it and thus grounds the private normalconductor 69 and the private bank contact of the connector bankscorresponding to the number of the substation A, so that no callingsubscriber may be able. to call in upon substation As line after acalling operation has once been started.

The repeater C is of the general type shown in my said applicationSerial No. 326.450. The spring 91 is provided in connection with a coil216, from which latter the trunk release conductor leads to the privatebank of the first-selector B, and to all other private banks in multiplethere with. The spring 91 is adapted to engage the spring 90, whichlatter has the retracti'ng means for restoring the armature 88. Saidspring 90 is connected to the nongrounded terminal of battery B forpurposes hereinafter described. The said repeater C, like the selectorB, is provided with a vertical line relay 69 and a rotary line relay 70,through the medium of which the said repeater is controlled. The saidrepeater is provided with a shaft 71 which carries a pair of wipers 72and 73 and which is operated by a rotary magnet 74. The shaft carriestwo sets of longitudinal teeth 75 and 70, the former being adapted to benormally engaged by the rotary pawl 77. The rotary magnet 74 is providedwith an armature 78, which latter is provided with an arm 79 upon theend of which the pawl 7 7 is pivotally mounted. A retractingspring 80 isadapted to always maintain a tension on the pawl 77 in the direction ofthe longitudinal teeth 75. A suitable adjustable stop 81 is mounted upona cross member 82 that is secured to the post 83. The said stop limitsthe stroke of the armature 78 toward the core of the magnet 74. Anotherstop .84 also mounted upon the cross member 82 limits the motion of thearmature 78 in the opposite direction. The said arm 79 controls a coupleof springs 85 and 86, the

former of which may be of heavy spring material and answers as aretracting force for restoring the armature 79 to normal condition andfor rotating the shaft 71 at the same time. It will be noticed thatthere are five longitudinal teeth 75 for rotating the shaft 71. The pawl77 rests against the second tooth when the shaft 71 is in normalposition. It is not absolutely necessary that there should be foursteps, as the shaft may be arranged to be provided with only three ortwo or any suitable number of steps, depending upon the size of theexchange and the number of digits in the number to be secured by therepeater. The number of steps necessary to carry the wipers 72 and 73 totheir respective bank contacts 92 and 93 may be readily changed, byadjusting the position of the stop 98 with respect to the stop pin 97.At each step of the shaft 71 the latter is retained by a ratchet 87 uponthe armature 88 that is controlled by a ratchet magnet 89. Thesaidratchet 87 also controls a couple of springs 90 and 91, the former ofwhich acts as a retracting means for maintaining the ratchet 87 inengagement with the longitudinal teeth 76. When the subscriber starts torelease, the rotary magnet 74 and the ratchet magnet 89 must then beenergized simultaneously so that the pawl 77 and ratchet 87 may besimultaneously disengaged from the shaft 71. The wipers 72 and 7 3 areadapted to engage the bank contacts 92 and 93 which are clamped in anysuitable manner to form a bank. Normally the wipers are out ofengagement with the said bank contacts, since the shaft is maintained innormal position determined by the adjustment of the pin 97 located onthe upper side of the shaft, and a stop member 98. The normal positionof the shaft is such that in the arrangement shown in Fig. 1 it takesthree steps to carry the wipers into engagement with the bank contacts92 and 93. The normal position of the wipers is shown in Fig. 1 by theline a, the first position by Z), the second position by 0, and thethird position by the bank contacts themselves. When the repeater islocated in the circuit, as shown in Fig. 1, and used as a terminal to atrunk line leading to another exchange, the local trunk conductors 9aand that connect the repeater C with the proper first-selector bankcontacts terminate in the wipers 72 and 73, and the trunk conductors 99and 100 that lead to the other exchange terminate in the condensers 101and 102, respectively, or in any other suit able electric connectingapparatus. The repeater as a whole is built upon a suitable base (notshown), the mechanism itself being assembled upon a frame (not shown)that is attached to the base. The condensers are usually packed betweenthe base and the frame. The switch-shaft 71 is retained in normalposition by any suitable means, such as the coil-spring 108. The line.relays 69 and 70 control the springs 110, 111, 112, 113 and 11 which areincluded in certain circuits to be described. In a system in which thesubscribers numbers have four digits the trunk conductors 99 and 100that lead from the repeater C to the central cities #2 terminate in asecond-selector.

The secondselector G is the same as the first-selector B, with theexception that there are no normal conductors, such as the normalconductors 115 and 116 that lead to the connector banks and over whichthe calling subscribers make connection with the substation A. There is,of course, no necessity for such conductors in the second-selector andthey are therefore omitted. There is also no necessity in thesecond-selector for such a relay as the bridge-cut-ofi-relay 68 of thefirst-selector B and it is, therefore, omitted and the vertical androtary line relays 117 and 118 are, respectively, connected directly tothe battery. There is also no requirement for a private normal conductorsuch as the private normal conductor 69, and the spring 119 controlledby the normal post arm 120 is connected through an oft-normal lamp 121for indicating when the secondselector is off normal. Whenever theswitch- .shatt is raised the normal post arm 120 clears the spring 119,which lattgr then passes into contact with the rounded contact justabove it, and thus estalfiishes an energizing circuit through the lamp121 from ground to the battery.

The connector-switch F may also be of any suitable or approved type,such as the connector described. in Patent No. 81'5,176. Themechanicaldetails of the selector and con'nector, as is well known, arevery much the same, althoughthere is some material difference in thecircuits. The connectorswitch shaft, like the shaft of the selectors,andwhich is not shown, carries the usual line wipers 122 and 123 and theprivate wiper 12-1. The connector-switch is also controlled by thecalling subscriber through the medium of the vertical and rotarylinerelay 124 and 125. The vertical line relay 124: directly controlsthe vertical magnet 126 and also the rotary magnet 127. The ofiice ofthe said vertical magnet 126 is to give the shaft and the shaft wiperstheir vertical movement, and the rotary magnet 127 imparts to the saidshaft a rotary or circular movement. The r'otary line relay 125 controlsthe private magnet 128, which latter under certain conditions in turncontrols circuits of the vertical and rotary magnets 126 and 127 and ofthe releasemagnet 129, and also the side switch wipers 130, 131, 132 and133, all of which are shown. The said side switch, like the side switchof the first-selector, has a normal or first position, a second positionand a third position. In normal position the respective side switchwipers engage the contact points 134, 135, 136 and 137. In secondposition the contact points 138, 139, 1 10 and 1 11, and in thirdposition the contact points 1 12, 1 13, 144 and 14:5. The release-magnet129 is also controlled bythe line relays 124 and 125. conjointly, and bythe back-bridgerelays 1 16 and 147 conjointly. Like the repeater theconnector dividesthe circuit that passes through it into two sections bythe use of the condensers 118 and 119. The connector has in addition aringer relay 150 by means of which the ringer generator 151 is bridgedacross the terminals of the called line to signal the called subscriber.Each exchange also has a busy signaling apparatus H of any suitabledesign, as, for example, an interrupter 152 in series with a secondarywinding 153 of an inductioncoil 154C, whereby a busy signaling currentis induced into the primary Winding 155 of the said induction-coil 154.Said primary windin 155 is connected to the contact point 156 againstwhich the switch-shaft spring 157 is allowed to press when the normalpost arm 158 is raised.

The first-selector E of the called line is the same as thefirst-selector B and needs, therefore, no description. The substation Dis also the same as substation A. t,

The trunk connection between the two exchanges may be arranged in anyconvenient manner, and it do not confine myself to any particulararrangement, since the system herein disclosed is variable. If it isassumed, for convenience, that the maximum number of subscribers to beaccommodated at each exchange is five thousand, then the first fivelevels of the first-selectors of exchange #1 may be devoted to localconnections, and the last five levels to trunk connections to exchange#2, each of which trunk connections, of course, comprising a repeatersimilar to the repeater C. The reverse would be the arrangement forexchange #2, as in that exchange the first five levels would be devotedto trunk operations to exchange #1 and the last five levels to localconnections. it do not limit myself to this arrangement even when themaximum number to be accommodated at each exchange is not to exceed fivehundred'; and it will be understood, of course, that all of the switchesmay be arranged in groups. For example, the first-selectors of the samegroup have all similar bank contacts connected in multiple. If eachgroup consists of one hundred selectors there Wlll be one hundred banks.Therefore, if any one of the selectors of a given hundred connect withthe repeater C a guarding potential will be established at the contactengaged by the private wiper 62 and at all other private bank contactsin multiple, so that all other selectors of the group, if they make acall, will pass over the trunk that leads to the repeater C withoutinterfering with the connection. The same grouping ar-. rangement, as iswell known, applies to the call the number 2229 the subscriber atsubstation A, as previously described, operates the dial once for eachdigit. The first operation of the dial results in the vertical line Tconductor 38 being rounded twice, and as a result the vertical linerelay 40 of the firstselector B is energized twice, the current in eachcase flowing from ground G through the ground springs 16 and 17 to theground post 15, thenceithrough the vertical lmpulse finger 14 to thevertical line conductor 38, side switch wiper 42, contact polnt 44,vertical line relay 40, bridge-cut-ofl-relay springs 159 and 160 to thebattery lead 161, and from battery B to ground G Each time that thevertical line relay 40 is energized the line relay springs 162 and 163are pressed into contact and an energizing circuit is therebyestablished through the ver tical magnet 59. Current through the saidmagnet flows from ground G through the springs 163 and 162, privatesprlngs 164 and 165, vertical magnet 59 to the battery lead 161 andthrough battery 18 to ground G The vertical magnet 59 then operates toralse the shaft for placing the wipers 60, 61 and 62 opposite a level inwhich are the contact points at which the trunk line conductors thatlead to the repeater C terminate. When the rotary line conductor 39 isgrounded the rotary line relay 41 is in turn energized, The currentthrough said relay flows through ground G to the ground post 15, thenthrough the rotary impulse finger 13 to the rotary line conductor 39,thence through the side switchwiper 43, contact point 45 to the rotaryline relay 41, bridgecut-ofi'relay springs 166, 159 and 160 to thebattery lead 161, thence through battery 18 to ground G The rotary linerelay in turn magnetizes the private magnet 48 by establishing a circuitthrough the line relay springs 167 and 163. The current for energizingthe private magnet flows from ground G through the line relay springs163 and 167 to the private magnet'48, thence through battery lead 161and through battery B to ground G The private magnet 48 then operates torelease the side switch from first to second position, and as a result acircuit is closed through the rotary magnet 63, when the side switchwiper 47 engages the contact point 54. The current through the vrotarymagnet flows from ground G to the contact point 54, thence through theside switch wiper 47,'one coil of rotary magnet 63, interrupter springs168 and 169, another coil of rotary magnet 63 to the battery lead 161,thence through battery B to ground G The rotary magnet is energizedstepby-step and the wipers 60, 61 and 62 are advanced in like mannerover busy contact Lemma points until the wipers find the first idletrunk line which, it is assumed, is the trunk G1 of the battery Bthrough the occupying switch to the private wiper 62, thence through theback-release-relay 170, side switch wiper 46, contact point 53, privatemagnet 48 to the battery lead 161, thence through battery B to ground GAt the instant that the private magnet 48 deenergizes, after passingover busy contacts, the side switch is tripped into third position, orit there are no busy contacts to be passed over, the rotary magnet 63,as is well known, trips the side switch to third position with theresult that as soon as the side switch wipers 42 and 43, respectively,engage the contact points 55 and 56 the subscribers line conductors 38and 39 are extended to the repeater C. Also, since the side switch wiper46 at the same time engages the contact point 57 a guarding potential isestablished at the private wiper 62 to protect the seized trunk linethat leads from the repeater C from being molested by any other switch.The second operation of the dial, since the line is new extended, isdirected to the re peater C. Grounding the Vertical line conductor 38twice energizes the vertical line relay 69 twice, the current in thiscase flowing from ground G to the ground post 15, thence through thevertical impulse finger 14 to the vertical line conductor 38, sideswitch wiper 42 of the selector B, vertical line wi er- 60, verticalline relay 69 of the repeater to the battery lead 161, and throughbattery B to ground G Each time that the said vertical line relay 69 isenergized the springs 110, 111 and 112 are pressed into contact. Thespring 110 connects through the ratchet magnet 89 to the spring 85, atwhich spring the circuit is open so that the operation upon the spring110 at this time is not of any consequence, but the closure of contactbetween the springs 111 and 112 grounds the vertical trunk conductor 99.This, of course, occurs each time that the vertical line relay 69 isoperated, Grounding the vertical trunk conductor 99 in turn operates theswitches at the exchange #2, which operation will be considered in duetime. WVhen the subscriber grounds the rotary line conductor 39 heenergizes the rotary line relay 70 of the repeater C, the currentflowing from ground G to the ground spring 15. thence to the rotaryimpulse finger 13, rotary line conductor 39, iirst-selector'side switchwiper 43, contact point 56, rotary line wiper 61, rotary line rela tothe battery lead 161, thence throughbattery B to ground G The operationof the rotary line relay causes the line relay springs 11 1-, 113 and112 to be pressed together. The closure of the contact between thesprings 113 and 112 sends a ground impulse to the rotary trunk conductor100 for operating the switches at the second exchange, and the effect ofthus grounding the rotary trunk conductor will be consideredhereinafter. The establishment of connection between the springs 11-1and 112, through the intervening spring 113, energizes the rotary magnet7-1 of the repeater C. The current passes from ground G" through thesprings 112, 113 and 111 to the rotary magnet 71 and to the battery lead161, thence through battery B to ground G The rotary magnet 74; uponenergizing attracts its armature 78 and thus operates the pawl 7 7 torotate the shaft 71 one step at the same time the springs 85 and 86 arepressed into contact, but just at this stage of the call the operationhas no effect. The vertical trunk conductor 99 terminates in the sideswitch wiper 171 of the second-selector G, and the rotary trunkconductor 100 terminates in the side switch wiper 172 of the saidselector. Therefore, grounding the vertical trunk conductor 99 twice, asdescribed in the preceding, operates the vertical line relay 117, thecurrent flowing from ground G? at the repeater C through the line relaysprings 112 and 111 to the vertical trunk conductor 99, thence throu hthe side switch wiper 171, contact point 1 3, vertical line relay 117 tothe battery lead 174, and through battery B to ground G The verticalline relay 117 in turn operates the vertical magnet 175, as described inconnection with the first-selector B, so that the shaft wipers 176, 177and 178 are raised'to that level with the contacts from which a trunkline leads to the connector F. As soon as the switch-shaft rises thenormal post arm 120 permits the switch-shaft spring 119 to.

engage the contact point 179, so that the 011'- normal lamp 121 flashesup and indicates that the said switch is in use. The grounding of therotary trunk conductor 100 in turn energizes the rotary line relay 118,which latter in turn energizes the private magnet 180 for a momentandpermits the side switch to escape from first to second position. Thecurrent through the said rotary line relay 118 flows from ground G atthe repeater C through the springs 112 and 113 to the rotary trunkconductor 100, through the side switch wiper 172, contact point 172',rotary line relay 118 to the battery lead 17 4, thence through battery Bto ground G As soon as the side switch wiper 181 engages the contactpoint 182 an energizing circuit is established through the rotary magnet183, which latter operates to rotate the shaft in the same manner thatthe rotary magnet of tho first-selector B operates. The current throughthe said rotary magnet 183 flows from ground G through the side switchwiper 181, rotary magnet 183 and its allotted interrupter springs'to thebattery lead 171 and through battery B to ground (i When ,the rotarymagnet operates, the side switch from establishing connection with thecon-' nector F. The third operation of the dial, since the subscribersline conductors are extended to the connector F, is directed to the saidconnector. When the vertical line conductor 38 is rounded twice thevertical line relay 69 of the repeater C is again operated twice,whereby the vertical trunk conductor 99 is again'grounded twice.Grounding the vertical trunk conductor 99 energizes the vertical linerelay 124 of the connector. The current through said relay flows fromground G to the vertical trunk conductor 99, thence through the sideswitch wiper 171, contact point 18%, vertical line wiper 176 to thevertical line relay 124, thence to the battery lead 171 and from batteryB to ground G The vertical line relay 121 in turn presses the line relaysprings 188 and 189 into contact, and as a result the magnet 126 isoperated. The current through said magnet fiows from ground G tothe-springs 189 and 188, private springs 190 and 191, side switch wiper133, contact point 137, vertical magnet 126 to the battery lead 174, andthrough battery B to ground G The vertical magnet 126, as usual,operates to raise the switch-shaft. Being operated twice the shaft israised two steps and the shaft wipers- 122, 123 and 124 are carried to alevel in which the line of the subscriber #2220 is located. When therotary line conductor 39 is grounded once the rotary line relay 70 ofthe repeater C is energized once as before, and as a result the rotarymagnet 71 of the repeater C is again operated once and the shaft 71rotated another step, and the wipers 72 and 73 carried to a positionmarked'by the lines C. At the same time the rotary trunk conductor 100is grounded once, causing the rotary line relay 125 of the connector Fto be operated. The current flows through the rotary relay 125 from tilll to the hotter lead 174, thence through hettery B to ground (2,

The rotary line reley 125 in turn energizes the private magnet 128 uponpressing the line relay springs 132 and 189 into contact. The currentthrough said private magnet passes from ground G through the springs 189and 192, private magnet 128 to the hettery lend lit, thence throughbattery B to ground G The private magnet being operated rnon'ientnrilycauses the side switch to pass from first to second position. As aresult the side switch Wiper 133 shifts into engagement with the contactpoint 1 H, substituting the rotary magnet 127 for the vertical 1%,snlojecting the former to the control the verticol line relay 12 i, Thefourth operotion ot the dial causes the verticel line conductor 38 to hegrounded again, the vertical line relay 69 ot the repeater he en er ed\2 LG again, and the vertical trunk conductor 9 to be grounded again,each ten times, since the fourth is the digit 0. lila ch that theverticel trunk conductor 9?: is grounded vertical line relay 1 .24 t

i opereted ov circ t pointed our, hot instead op sting in turn or evertical magnet 12% ontlie r y niegnet 12? each time The circuit seidmagnet tends ll "onnl G to the side svvi s. T e the contact poi y tnrymagnet y i s 1 one through .tcn snort is more 122,

station the rotary: line conduct-r A; lost time energizes li 2y "-4 0oithe repester C, which in couses of the rotery e 7%, whereby the shaft7 is rotnted enotne" o and the Wipers 72 '73 carried c gernent with thecont set points 92 end 98,

respectively. At the some time the rotery conductor is grounded once.Grounding the rotary trunlr conduc tor lOtl energizes the rotary linereley 3125 oi the connector F, the energization oft "which relay causeseither the release of the connector-switch, the celled is lousy, or therelease o1 the side switch. from second third posit itthe line is notbusy, which letter operetion pieces the side switch Wipers 130 and 131in engegenient With the contact points and 1%, thus placing snhecrioer sline in connection I w inverts the celled suhscrihers line through thecondensers 14:8 and M9. The connection is marked by heavy lines'in Figs.l and 2, It will be assuincd'tirst that the energizetion oi the rotaryline relay produces the letter TGSUll F-lIhHLlZ is, releases theconnector side switch to third position, lt will be noticed that theceiling subscribers vertical line conductor 38 extends through thevertical side switch Wiper i2 and the verticel line Wiper 60 of thefirst-selector B to the vertical Wiper 72 of the repeater C, whichletter being non in engagement with the contact point 92 QXtQllClS thecircuit through the condenser 101 to the vertical trunk conductor 99,thence through the side switch Wiper 171 and vertical line Wiper 176 oi.the secondselector G to the connector condenser H8, thence through therim? i relay springs 196 end 197, side switch wiper to the vertical lineWiper 12%, normal conductor 193, cu led suhscribers vertical lineconductor 19%, through the substation ringer 199 to rotary lineconductor i200 and hock to the rotery noriniil conductor 1%, line Wiper123, side switch 131, ringer reley- 201 2&2, enser line Wiper 17?,

side sivitc oer N2 of the secondselector G, rot tr enlt conductor ltltl,condenser 102, cc toot "point 93 and rotary Wiper 73 oil the r peeter C,rot-cry line Wiper 1 side o itch Wiper L3 or the first-selector B to erotary line conductor 39, thence thrc' the receiver Q, secondary WindingQtli Q; the induction-coil 5 hoe: to the vertical i re conductor 38.

To signal the celled subscriber the cellingsuhscriher pre%es hissignaling huh n 3e'ltherehy grounding the vertical line con- ;dnctor 88over e circuit that vextra-uncle from ground the ground springs to andi7, conductor 204:, contact point 37', spring- 35 to the vertical lineconductor 38.,

As a result the vertical line relny 69 of the repeater C is energized,which letter then grounds the vertical trunk conduct causing turn theenergizaition of verticsl line r ,ey of the connector 1?, Seid relaysince the side switch Wiper 138 is in third position, causes the ringerreley to become n'izignetized. The current through seid ringer relaytloivs from ground G to the side switch Wiper 133, thence through theringer reley ion to the battery lead 174- end through loztttery B toground G The ringer relay upon attracting its armature forces the ringerreley springs 201 end l9? onto the ringer reley springs 205 end 206,thus loreelring the connection between the calling subscriber end thecalled ter. in order to prevent the ringing current from interferingwith the line releys as the connector side switch wiper 132 en-i gagesthe grounded contact point 144. The circuit through saidbridge-cut-off-relay extends from ground G through the side switch wiper132 to the private wiper 124,

conductor 195, thence through the switch shaft springs 210 and 211 tothe bridge-cutoff-relay 209, thence to the battery lead 174 and throughbattery B to ground G The said relay 209 upon energizing separates thesprings 212, 213 and 214, thereby breakin the connection between thesaid relays 207 and 208 and battery lead, and between each other,leaving the line clear at the selector E. The same circuit that connectsground Gr through the side switch wiper 132 with the connector privatewiper 124 is used for establishing a guarding potential that protectsthe seized line from interference by some othersubscriber. Busy linesare protected, as described, by guarding potentials. The calling line isprotected by guarding potential established at the connector-banks fromthe selector B of the calling line, and

the called line is protected by a guarding potential established by theconnector. In either case if the line is busy, therefore, there is aguarding potential at the private bank contact that corresponds to thenumber of his line. Digressing for a moment it will be assumed that thecalled line #2220 is busy at the time that the rotary line relay 125 ofthe connector F is energized. The said relay, as is shown, in turncauses the energization of the private magnet 128, which latter thenpresses the springs 214' and 215 into contact, As a result the releasemagnet 129 is placed in connection with the private wiper 124, whichlatter has been previously rotated onto a grounded contact. As a resultthere is sent a flow of current through the release magnet 129 from theprivate wiper 124 to the side switch wiper 132, which is now in secondposition,

contact point 140, private springs 214 and 215, release magnet 129 tothe battery lead 174 and through battery 1? to ground G As a result therelease magnet becomes magnetized and the connector-switch is releasedand restored to normal condition. Then when the subscriber presses hissignaling button and grounds the vertical line conductor 38 he energizesthe vertical linerelay 69 at the repeater C, grounds. the vertical trunkconductor 99 and energizes the vertical line relay 124 of the connector.Since the side switch is now in first position, the connector havingbeen released, thevertical magnet 126 is energized and the switch-shaftis raised so that the switchshaft springs 157 and 156 close connection Acircuit is thus established from the busy coil 155 of the busy machine Hthrough the switch-shaft springs 156 and 157, side switch Wiper 1 31,ringer relay springs 201 and 202, condenser 149 to the callingsubscribers rotary line conductor 39 over circuits that have beendescribed, through the receiver 2 back to the vertical line conductor38, thence to the vertical trunk conductor 99 and to the vertical linerelay 124 of the connector to the battery lead 174 and back to the busycoil 155. The -calling subscriber upon hearmg the busy signal releaseshis switching apparatus at the central oflice. The release occurs whenthe calling subscriber restores his receiver 2 and thus presses thereleasesprlngs 31., 32 and 33 into contact and thus simultaneouslygrounds the vertical and rotary line conductors 38 and 39 for a moment.Grounding the vertical and rotary line conductors 38 and 39simultaneously energizes the vertical and rotary line relays 69 and 70of the repeater C at the same time, whereby all of the springs 110, 111,112, 11'3-and 114 are pressed into contact. As a result the rotarymagnet 74 is magnetized, the ratchet magnet 89 is magnetized, and thevertical and rotary trunk conductors 99 and 100 aregroundedsimultaneously. The

circuit through the rotary magnet 74. is known. The energizing circuitthrough the ratchet magnet 89 extends from ground G through the springs112, 111 and 110 to the ratchet magnet 89, thence through the springsand-86 to the battery lead 161 and through battery B to ground G Whenthe ratchet magnet 89 forces the springs 90 and 91 into contact anenergizing pircuit is established through the back-reease-relay 170 ofthe first-selector B. Current in this ircuit passes from ground G atthe. first-selector B, side switch contact point 57, side switch wiper46, back-releaserelay 170, private wiper 62, resistance coil 216 of therepeater C, springs 91 and 90 to the battery lead 161, thence throughbattery B to ground G The back-release-relay 170 upon magnetizingpresses the springs 217 and 218 in contact, setting up in turn, as aresult, a magnetizing circuit through the release-magnet 64 of thefirst-selector'B. As soon as the rotary magnet 74 of the repeater C andthe ratchet magnet 89 attract their armatures, the switch-shaft 71 andwipers 7 2 and 7 3 are restored to normal condition by the tension ofthe retracting spring 108. The vertical and rotary trunk conductors 99and- 100 being grounded at 'the same time, as previously stated, causethe vertical and rotary line relays 124 and 125 of the connector Ftoenergize at the same time, and thus force the trunk release nector inseries with the back release-relayf 221 of the second-selector Thisrelease The back-release-relay 221, however, upon energizing presses thesprings 222 and 223 into contact, thereby energizing the releasemagnet224 ofthe second-selector in the same manner that the release-magnet 64of the first-selector Bflwas energized. As soon as the subscribersrelease-springs 31, 32 and 33 disengage, the line relays 69 and 70of'the repeater C deenergize, and the rotary-magnet 74 andthe ratchetmagnet 89 of the repeater C deenergize, which ratchet magnet uponpermitting the springs 91 and 90 to separate destroys the energizingrelease circuit that leads to the selector B, at which time the selectorB is fully restored. The reinoval of the ground. connection from thetrunk conductors 99 and 100 causes the deenergization of the verticaland rotary relays 124 and 125 of the connector F. When the saidconnector relays 124 and 125 deenergize the trunk release springs 219and 220 separate, and as a result the energizing circuit throughtheback-release-relay 221 of the second-selector G and through therelease 7 maget 129 of the connector F is destroyed.

The connector F is thus left fully restored. The deenergization of theback-release-relay 221 of the selector G causes the de'einergization ofthe release-magnet 224, which latter, as is well known, then causes therestoration of the selector switch shaft and side switch The callingsubscriber thus restores all the switching apparatus which he originallybrought into use. However, if the line is not busy, and the calledsubscriber answers, by removing his receiver 225 from the switch-hook hethus bridges his secondary circuit, which includes thesaid receiver andthe secondary winding 226 ofhis inductioncoil, across the line. I Thecalling and called subscribers are thus connected for conversation overthe heavily marked conductors shown in Figs. 1 and 2, which conductorshave already been pointed out. After the subscribers are-throughcommunicating the calling subscriber may destroy the establishedconnection by hanging up his receiver and grounding as a result thevertical and rotary line conductors 38 and 39 simultaneously, as alreadydescribed. As a result the line relays 69 and 70 of the repeater Cbecome energized simultaneously. Said relays in turn, as has beendescribed, ground the trunk conductors 99 and 100, when the springs 111,112 and 113 are pressed into contact, thus in turn causing thecnergization of the line relays 124 and 125 of the connector F. Theconnector-switch, of course, is thus released in the same manner 70described in connection with the release when the calling subscriberreceives the busy signal. There is one slight diflerence, however, andthat is that the connector switch shaft which is now rotated firstreturns to normal rotary position and then falls to normal verticalposition, as is well known. As soon as the shaft of the connector F isreleased from engagement with the trunk line leading to the calledselector E so the private wiper 124 breaks connection with the privatenormal conductor 195 and the energizing circuit for the bridge-cutoff-relay 209 is destroyed. As a result the line relays 207 and 208 ofthe selector E regain their normal condition and return under thecontrol of the substation D. The release-magnet 129 of the connector F,of course, energizes in series with the back-release relay 221 of theselector G, as previously pointed out, which latter relay 221 in turnenergizes the release-1nagnet 224; so that as soon as the relays 124and125 deenergize the back-release-relay 221 also deenergizes, as wellas the release-magnet 224, with the result that the selector G is alsorestored. The simultaneous energization of the repeater line relays 69and 70 causes the simultaneous ener ization of-the rotary and ratchetmagnets 4 and 89, respectively, and the establishment of a releasecircuit through the back-release relay 170 of the first-selector B whenthe springs 90 and 91 of the repeater C are brought into contact. Thesaid back-release-relay 170 in turn causes the energization of thereleasemagnet 64, but the circuit of the said release-magnet is alsobroken when the release-springs 31, 32 and 33 separate, and, of

course, when the line relays 69 and 70 deenergize. The final result isthat the switch- *ing apparatus involved in establishing con nection isall restored to normal condition ready for another call.

The back release is provided in order that the called subscriber may notremain helplessly tied up, so to speak, while the bridgecut-ofi -relay209 is energized, should he desire, before the calling subscriberreleases, to break the established connection and 12a make anindependent call. If he should desire to acquire control of hisfirst-selector E,

after establishing connection between the ground springs 230 and 231, byoperating the dial, he may ground hisline conductors 198 and 200simultaneously by restoring his receiver 225 and thus pressing thereleasesprings 22?, 228 and 229 into contact. As a result an energizingcircuit will be set up through the vertical back-bridge-relay. 146 weand the rotary back-bridge-relay 147 of the connector F. The ener izingcircuit through the vertical back-bri ge-relay may be traced from groundG through the springs 230 and 231 to the ground releasethence throughthe ringer relay springs 201 and 202 and through the rotaryback-bridgerelay 147 to the battery lead 174 and through battery B toground G The said relays 146 and 14:7 upon energizing simultaneouslyforce the springs 232 and 233 into contact,

establishing an energizing circuit for the re-- lease-magnet 129 fromground G through the springs 232 and 233, release-magnet 129 to thebattery lead 174, thence through battery B to ground G Therelease-magnet of the connector F is thus energized, the wipers 122, 123and 12 i disconnected from the first-selector E and the energizingcircuit through the bridge-cut-off-relay 209 destroyed, leaving thefirst-selector E and the connector F .fully restored, the former beingreturned to the control of the calling subscriber. The callingsubscriber may then, by grounding his line conductors 38 and 39, uponhanging up his receiver, restore the remaining switches B, C and G. Itwill be evident from the structure and description of the repeater Othat the said switch is adapted to be inserted in any part of thecircuit, between any ofthe switches or in any other positionwhere therepetition of impulses and the transmission of voice-currents isrequired, as described in the pre ceding.

The resistance of the coils 69, 70, 74:, 89 and 216 may be of anysuitable character, but good results are obtained when the coils 69 and'70 are wound to a resistance ,of five hundred ohms each, and the coils741, 89 and 216 to sixt ohms each.

Obvious y, with the use of my repeater the subscribers of two difierentexchanges, which may be a considerable distance apart, may easily obtainconnection with each other, notwithstandin the fact that the distancebetween the ca ling exchange and the exchange to which the calledsubscriber belongs may be so great that ordinarily the resistance of thelines would be too 1great to successfully operate, directly, the remagnets of the switches in the distant exchange, and too great for asatisfactory use of three-conductor trunk lines. Under such conditions,the repeater G acts as a relay station for the switch operating impulsesthat originate in the calling substation. It will ays and between theexchanges.

end of the same trunk line, in place of the be evident, then, that Wherethe exchanges are not so far apart the trunk conductors 99 and 100 maybe made of material which is cheaper even if of comparatively highresistance, such as iron, instead of making it necessary to use copperfor the trunk lines If for any reason it should be desirable to have tworepeaters, for example, one at the end of the trunk line, as shown inFig. 1, and one at the other second-selector G, there is no reason whysuch an arrangement should not be employed. My repeater, it will beevident from its construction, is adapted to be thus arranged'in thecircuit. It is not even necessary that the repeater should be used totransmit impulses from one exchange to the other, as it may be used totransmit im pulses between switches wherever theytmay be located.

' The hub of the re eater C that carries the longitudinal teeth 5 and 76may, if v desired, be either riveted to the shaft or se- 1 cured theretoby means of a screw or other ,90 device. The object in providing anormally disconnected circuit between the local trunk conductors 94; and95 that connect therepeaterC with ,the banks of the selector B and theoutgoing trunk conductors 99 and 100 is to precludethe'impulseswhich.operate the relays 69 and 70 from discharging through the condensers 101and 102 and thus perhaps afiecting the relays at the second: selector G.Better results are obtainedy'by this form of construction.

From th foregoing it will be seen that the repeater relay 89'has thedouble function of closing a trunk release circuit back over a thirdtrunk conductor to the first-selector B, 105 andof mechanicallyreleasing or restoring the line wipers 72 and 73 to normal position.With this arrangement the bridged line relays of the selectors can becut oil from the talking circuit during use of same for conversatlonalpurposes, and at such time the only relays left across the circuit arethose of the .repeater and the connector. When the subscribers arethrough talking the release is initiated over the line circuit byenergizing the line relays of the repeater, and this in turn groundsboth of the trunk line conductors 99 and 100, causing a simultaneousenergizing of the line relays of the connector. This, of course, asexplained, enables the connector to close a trunk release circuitextendingback to the second-selector G, and enables the repeater to inturn close a trunk release circuit extending back tothe first-selectorB. In other words, the connector releases itself and thesecond-selector, and the re ater releases itself and the first-selector.W i h such an arrangement three trunk line conductors are necessarybetween the firstselector and the repeater, and between the Killsecond-selector and the connector, but only two conductors are necessarybetween the repeater and the second-selector, while only two bridges areretained for releasing purposes, namely the line relay bridges of therepeater and the connector.

\Vhat I claim as my invention is 2- 1. In a telephone exchange system,the combination of a telephone line circuit extending between callingand called subscribers substations, an automatic switch provided withrelay means temporarily disconnected from said circuit, a repeaterprovided with means for repeating or relaying electrical-impulses fromone portion of said circuit to another, means in said repeater forclosing connection between the said portions of the line circuit, anelectromagnet for releasing said circuit-closing means in the repeater,a trunk release circuit extending between the automatic switch and therepeater, normally open contacts included in the re peater andcontrolled by said electromagnet, said contacts controlling thecontinuity of said trunk release circuit, and means for supplyingelectrical current for operating said automatic switch and repeater.

2. In a telephone system, a telephone line,

means for sending impulses over said line, a repeater, means forconnecting said line with said repeater, a switch, a line extending fromsaid repeater to said switch, a second switch, electromagnetic means insaid repeater responsive to said impulses it'or oper ating said switchesto build a line connection from the repeater to a second telephone lineand to signal said second telephone line, progressively movable means insaid repeater for connecting the first line with the switch line'afterthe first switch is operated whereby a connection is established betweenthe first line and the second line, means for releasing said switchescontrolled by said repeater, and releasing means for disconnecting thefirst line from said first switch, said first releasing means comprisingcircuits between the switches separate trom the talking circuit.

s 3. In a telephone system, a telephone line, means for sending impulsesover said line, a repeater, means for connecting said line with saidrepeater, a switch, a line connecting said switch with said repeater,and means in said repeater responsive to said impulses for operatingsaid switch, and means for connecting said telephone line with saidswitch line after the switch isoperated, releasing mechanisms in saidswitch and in said second means and circuits for operating thesaidmechanisms from said repeater in response to said impulse sendingmeans, one of said release circuits involving a conductor separate fromthe talking circuit.

4:. In a telephone system, a telephone line means in said switch forconnecting said line with said repeater, a second switch, a

line connecting said repeater with said second switch, means in saidrepeater responsive to said impulses for operating said second switch,and means for connecting said telephone line with said switch line afterthe second switch is operated, releasing devices in said second switchand in said first switch and circuits for operating the same controlledfrom said repeater in response to said impulse sending means, one ofsaid release circuits involving a conductor separate from the talkingcircuit.

5. In a telephone system, a telephone line, means for sending impulsesover said line, a repeater, means for connecting said line with saidrepeater, a switch, a line connecting said switch with said repeater andelectromagnetic means in said repeater responsive to said impulses foroperating said switch, and means for connecting said telephone line withsaid switch line after the switch'is operated, releasing mechanisms insaid switch and in said second means and circuits for operating the saidmechanisms from said repeater in response to said impulse sending means,one of said release circuits involving a conductor separate fromthetalking circuit.

6. In a telephone system, a telephone line, means for sending impulsesover said line, a switch associated with said line, a repeater, means insaid switch for connecting said line with said repeater, a secondswitch, a line connecting said repeater with said second switch,electromagnetic means in said repeater responsive to said impulses foroperating said second switch, and means for connecting said telephoneline with said switch line after the second'switch is operated,releasing devices in said second switch and in said first switch andcircuits for op erating the same controlled from said repeater inresponse to said impulse sending means, one of said release circuitsinvolving a conductor separate from the talking circuit.

7. In a telephone system, a telephone line, means for sending impulsesover said line, a repeater, means for connecting said line with saidrepeater, a switch, a line connecting said switch with said repeater,and means in said repeater responsive to said impulses tor operatingsaid switch, and progressively movable means t'or connecting saidtelephone line with said switch line after the switch is operated,releasing mechanisms in said switch and in said second means andcircuits for operating the said mechanisms from said repeater inresponse to said impulse sending means, one of said release circuitsinvolving a conductor separate from the talking circuit.

Mill

act

8. In a telephone system, a telephone line, means for sending impulsesover said line, a switch associated with said line, a repeater, means insaid switch for connecting said line with said repeater, a secondswitch, a line connecting said repeater with said second switch, meansin said repeater responsive to said'im ulses for operating said secondswitch, {111$ progressively movable means for connecting said telephoneline with said switch line after the second switch is operated,releasing devices in said second switch and in said first switch andcircuits for operating the same controlled from said repeater inresponse to said impulse sending means, one of said release circuitsinvolving a conductor separate from the talking circuit.

9. In a telephone system, a telephone line, means for sending impulsesover said line, a repeater, means for connecting said line with saidrepeater, a switch, a line con-- nectingsaid switch with said repeater,means in said repeater responsive to said impulses for operating saidswitch, and means for connecting said telephone line with said switchline after the switch is operated, re-

leasing mechanism in said switch, releasing mechanism in said secondmeans, a first release circuit for operating said first releasingmechanism, a second release circuit for operating said second releasingmechanism,- said release circuits-controlled from said repeat-er inresponse to said, impulse sending means, said second release circuitbeing separate from the talking circuit.

10. In a telephone system, a telephone line, means for sending impulsesover said line, a switch associated with said line, a repeater, means'insaid switch for connecting said line with said repeater, a secondswitch, a line connecting said repeater with said second switch, meansin said repeater responsive to said impulses for operating said secondswitch, and means for connecting said telephone line with said switchline after the second switch is operated, a releasing-device in saidsecond switch, a releasing device in said first switch, a first releasecircuit for controlling said first releasin device, a second releasecircuit for contro ling said second'releasing device, both of saidreleasing devices being controlled from the repeater responsive to saidimpulse sending means, said second release circuit being separate fromthe talking circuit.

11. In a telephone system, a telephone line, means for sending impulses.over said line, a repeater, means for connecting said lines with saidrepeater, a switch, a line connecting said switchwith said repeater,electromagnetic means in said repeater responsive to said impulses foroperating said switch, and means for connecting said I peater, means vline,

second release circuit for operating said second releasing mechanism,sald release circuits controlled from said repeater in reto said impulsesending means, said being separate from sponse second release circuitthe talking circuit;

12. In a telephone system, a telephine line, means for sending impulsesover said line, a switch associated with said line, a rein said switchfor'connecting said line with said repeater, a second switch, a lineconnecting said repeater with said second switch, electromagnetic meansin said repeater responsive to said impulses for operating said secondswitch, and means for connecting said telephone line with said switchline after the second switch is operated, a releasing device in saidsecond switch, a releasing device in said first switch, a first releasecircuit for controlling said first releasing device, a second releasecircuit for controlling said second releasing device, both of saidreleasing devices being controlled from the repeater responsive to saidimpulse sending means, said second release circuit being separate fromthe talking circuit.

13. In a telephone system, a telephone line, means for sending impulsesover said a repeater, means for connecting said 1ine with said repeater,a switch,'a line connecting said switch .with said repeater, means insaid repeater responsive to said impulses for operating said switch, andprogressively movable means for connecting said telephone line with saidswitch line after the switch is operated, releasing mechanism in saidswitch, releasing mechanism in said second means, a first releasecircuit for operating said second release circuit for operating saidsecond releasing mechanism, said release circuits controlled from saidrepeater in response to said impulse sending means, said second releasecircuit being separate from the talking circuit.

14. In a telephone system, a telephone line, means for sending impulsesover said line, a switch associated with said line, a repeater, means insaid switch for connecting said line with said repeater, a secondswitch, a line connecting said repeater with said second switch, meansin said repeater responsive to said impulses for operating said secondswitch, and progressively movable means for connecting said telephoneline with said switch line after the second switch is operated, areleasing device in said second switch, a releasing device in said firstswitch, a first release circuit for controlling said first releasingmechanisnn-a first releasing device, a second release circuit forcontrolling said second releasing device, both of said releasing devicesbeing controlled from the repeater responsive to said impulse sendingmeans, said second release circuit loeing separate from the talkingcircuit. A

15. In a telephone system, a telephone line, means for sending impulsesover said line, a repeater, means for connecting said line with saidrepeater, a switch, a line connecting said switch with said repeater andmeans in said repeater responsive to said impulses for operating saidswitch, and means for connecting inductively said telephone line withsaid switch line after the switch is operated, releasing mechanisms insaid switch and in said second means and circuits for operating the saidmechanisms from said repeater in response to said impulse sending means,one of said release circuits involving a conductor separate from thetalk ing circuit.

16. In a telephone system, a telephone line, means for sending impulsesover said line, a switch associated with said line, a repeater, means insaid switch for connecting said line with said repeater, a secondswitch, a line connecting said repeater with said second switch, meansin said repeater responsive to said impulses for operating said secondswitch, and means for connecting inductively said telephone line withsaid switch line after the second switch is operated, releasing devicesin said second switch and. in said first switch and circuits foroperating the same controlled from said repeater in response to saidimpulse sending means, one of said release circuits involving aconductor separate from the talking circuit.

117. In a telephone system, a telephone line, means for sending impulsesover said line, a repeater, means for connecting said line with saidrepeater, aswitch, a line con necting Said switch with said repeater andelectromagnetic meansoin said repeater responsive to said impulses foroperating said switch, and means for connecting inductively saidtelephone line with said switch line after the switch is operated,releasing mechanisms in said switch and in said second means andcircuits for operating the said mechanisms from said repeater inresponse to said impulse sending means, one of said release circuitsinvo ving a conductor separate from the talking circuit.

1& In a telephone system, a telephone line, means for sending impulsesover said line, a switch associated with said line, a repeater, means insaid switch for connecting line with said repeater, a second switch, aline connecting said repeater with said second switch, electromagneticmeans in. said repeater responsive to said impulses for opera-ans," saidswitch, means for connecting inductively said telephone line with saidswitch line after the second switch is operated, releasing devices insaid second switch and in said first switch and circuits for operatingthe same controlled from said repeater in response to said impulsesending means, one of said release circuits involving a conductorseparate from the talking circuit. I r 19. In a telephone-system, atelephone line, means for sending impulses over said line, a repeater,means for connecting said line with said repeater, a switch, a lineconnecting said switch with said repeater, and means in said repeaterresponsive to said impulses for operating said switch, and progressivelymovable means for connecting inductively said telephone line with saidswitch line after the switch is operated, releasing mechanism in saidswitch and in said second means and circuits for operating the saidmechanisms from said repeater in response to said impulse sending means,one of said release circuits involving a conductor separate from thetalking circuit.

20. lln a telephone system,.a telephone line, means for sending impulsesover said line, a switch associated with said line, a repeater, means insaid switch for connecting said line with said repeater, a secondswitch, a line connecting said repeater with said second switch, meansin said repeater responsive to said impulses for operating said secondswitch, and progressively movable means for connectin inductively saidtele phone line with said switch line after the second switch isoperated, releasing devices in said second switch and in said firstswitch and circuits for operating the same controlled from said repeaterin response to said impulse sending means, one of said release circuitsinvolving a conductor separate from the talking circuit.

inc

21. In a telephone system, a telephone line,

with said repeater, a switch, a line connect,

ing said switch with said repeater, means in said repeater responsive tosaid impulses for operating said switch, and means for connectinginductively said telephone line with said switch line after-the switchis operated, releasing mechanism in said switch, releasing mechanism insaid second means, a first release circuit for operating said firstreleasing mechanism, a second release circuit for operating said secondreleasing mechanism, said release circuits controlled from said repeaterin response to said impulse sending means, said second release circuitbeing separate from the talking circuit.

22. in a telephone system, a telephone line, means for sending impulsesover said line. a switch associated with said line, a repeater, means insaid switch for connecting said line with said repeater, a secondswitch, a line connecting said repeater with said second switch, meansin said repeater responsive to said impulses for operating said secondswitch, and means for connecting inductively .said telephone line withsaid switch line after the second switch is operated. a releasing devicein said second switch, a releasing device in said ,first switch. a firstrelease circuit for controlling said first releasing device, a secondrelease circuit for controlling sald second releasing device. both ofsaid releasing devices being controlled from the repeater responsive tosaid impulse sending means, said second release circuit being separatefrom the talking circuit.

23. In a telephone system, a telephone line, means for sending impulsesover said line, a repeater. means for connecting said line' with saidrepeater, a switch, a line connecting said switch with said repeater,electromagnetic means in said repeater responsive to said impulses foroperating said switch, and means for connecting inductively saidtelephone line with said switch line after the switch isoperated,-releasing mechanism in said switch, releasing mechanism insaid second means, a first release circuit for operating said firstreleasing mechanism, a second release circuit for operating said secondreleasing mechanism, said release circuits controlled from said repeaterin response to said impulse sending means, said second the talkingcircuit.

24. In a telephone system, a telephone line, means for sending impulsesover said line, a switch associated with said line, a repeater, means insaid switch for connecting said line with said repeater, a secondswitch, a lineconnecting said repeater with said second switch,electromagnetic means in said repeater responsive to said impulses foroperating said second switch, and means for connecting inductively saidtelephone line with said switch line after the second switch isoperated, a releasing device in said second switch, a releasing devicein said first switch, a first release circuit for controlling said firstreleasing device, a second release circuit for controlling said secondreleasing device, both of said releasing devices being controlled fromthe repeater responsive to said impulse sending means, said secondrelease circuit being separate from the talking circuit.

25. In a telephone system, a telephone line, means for sending impulsesover said line, a repeater, means for connecting said line with saidrepeater, a switch, a line connecting said switch with said repeater,means in said repeater responsive to said impulses for operating saidswitch, and progressively movable means for conrelease circuit beingseparate from necting inductively said telephone line with said switchline after the switch is operated, releasin mechanism in said switch,releasing mec anism in said second'means, a first release circuit foroperating said first releasing mechanism, a second release circuit foroperating said second releasmechanism, said release circuits controlledfrom said repeater in response to said impulse sending means, saidsecond release circuit being separate from the talking circuit.

26. In a telephone system. a telephone line. means for sending impulsesover said line. a switch associated with said line, a repeater, means insaid switch for connecting said line with said repeater, a secondswitch, a line connecting said repeater with said second switch, meansin said repeater responsive to said impulses for operating said secondswitch, and progressively movable means for connecting inductively saidtelephone line with said switch line after the second switch isoperated, a releasing device in said second switch, a releasing devicein said 'first switch, a first release circuit for ond release circuitfor controlling said second releasing device, both of said releasingdevices being controlled from the repeater responsive to said impulsesending means. said second release circuit being separate controllingsaid first releasing device, a seefrom the talkin circuit.

27. In a telep one system, a telephone line, means for sending impulsesover said line, a switch associated with said line, a repeater, means insaid switch 'for connecting said line with said repeater, a secondswitch, a line connecting said repeater with said second switch, meansin said repeater responsive to said impulses for operating said secondswitch, and means for connecting said telephone-line with said switchline after the second switch is operated, releasing devices in saidsecond switch and in said first switch and circuits for operating thesame controlled from said repeater in response to said impulse sendingmeans.

28. In a telephone system, a telephone line, means for sending impulsesover said line, a repeater, means for connecting said line with saidrepeater, a switch, a line connecting said switch with said repeater andelectromagnetic means in said repeater responsive to said impulses foroperating said switch, and means for connecting said telephone line withsaid switch line after t-hswitch is operated, releasing mechanism ansaid switch and in said second means and circuits for operating the saidmechanisms peater in response to said impulse means.

29. In a telephone system, a telephone line, means for sending impulsesover said line, a

' said line, a repeater,

sending switch associated with from said rcv switch, e

means for sending impulses means in said switch for connecting said linewith said repeater, a second switch, a line said repeater with saidsecond ectromagnetic means in said resaid impulses for operpeaterresponsive to and means for connecting said telephone line with saidswitch v saldfirst's witch and circuits for operating the samecontrolled from said repeater in response to said impulse sending means.

30. In a tele hone system, a telephone line, means for sen ing impulsesover said line, a repeater, means for connecting said line with saidrepeater, a switch, a line connecting said switch with said repeater,means in said repeater responsive to said impulses for operating saidswitch, and progressively movable means for connecting said telephoneline with said switch line after the switch is operated, releasingmechanism in said switch and in said second means and circuits foroperating the, said mechanisms from said repeater in response to saidimpulse sending means.

31. In a telephone system, a telephone line, means for sending impulsesover said line, a switch associated with said line, a repeater, means insaid with said repeater, a second switch, a line connecting saidrepeater with said second switch, means in said repeater responsive tosaid impulses for operating said second switch, and progressivelymovable means for connecting said telephone line with said switch lineafter the second switchis operated, releasing devices in said secondswitch'and in said first switch and circuits for operating the samecontrolled from said repeater in response to said impulse sendingmeans,

32. In a telephonesystem, a telephone line,

over said line, a repeater,.means for connecting said line with saidrepeater, a switch, 9 line connecting said switch with said repeater,means in said repeater responsive to said impulses for operating saidswitch, and means for connectin said telephone line with said switchline ater the switch is operated, releasing mechanism in said switch,releasing mechanism in said second means, a first release circuit foroperating said first releasing mechanism, a second release circuit foroperating said second releasing release circuits controlled from saidrepeater 1 said impulse sending means. stem, a telephone in response to33. In a telephone s line, means for sending impulses over said me, aswitch associated with said line, a repeater, means in said switch forconnectmg said line with said-repeater, a second switch, a lineconnecting said repeater with said second switch, means in said repeater.slve to said impulses for switch for connecting said line a increaseafter the second switch is operated, a releasing device in said secondswitch, a reimpulse sending 34.. In a telephone system, a telephoneline, means for sending impulses over said line, a repeater, means forconnecting said line with said repeater, a switch, a line connectingsaid switch with said repeater, electromagnetic means in'said repeaterresp releasing d means, a first rel ating said first release releasecircuit 35. In a telephone system, a telephone l ne, means for sendingimpulses over said line, a switch associated with said line, a

means in said switch for connector controlling said second releasingdevice, devices being con- "ng means. 36. In a telephone system, atelephone l ne, means for sending impulses over said me, a repeater, forconnecting said line with said for operating said switch, andprogressively for connecting said tele me with said switch line afterthe switch 13 operated, releasing mechanism in said switch, releasingmechanism in said second means, a first release circuit for operatingsaid first releasing mechanism, a second re-, lease circuit foroperating said second releasing mechanism, said release circuitcontrolled om said repeater in response to said impulse sending means.

37. In a telephone system, a telephone line, means for sending impulsesover said I line, a switch associated with said line, --a repeater,means in saidswitch for connecting said line with saidrepeater, a secondswitch, a line connecting said repeater with said second switch, meansin said repeater responsive to said impulses -for operating the secondswitch, and progressiyely movable means for connecting said telephoneline with said switch line after the second switch is operated, areleasing device in said second switch, a releasing device in said firstswitch, a first release circuit for controlling said first releasingdevice, a second release circuit for controlling said second releasingdevice, both of said releasing devices being controlled from therepeater responsive to said impulse sending means. I v

38. In a telephone system, a telephone line, means for sending impulsesover said line, a repeater, means for connecting said line with saidrepeater, a switch, a line connecting said switch with said repeater andmeans in said repeater responsive to sald impulses for operating saidswitch, and means for connecting inductively said telephone line withsaid switch line after the switch is operated, releasing mechanisms insaid switch and in said second meansand circuits for operating the saidmechanisms from said repeater in response to said 1mpulse sending means.I

39. In a telephone system, a telephone line, means for sending impulsesover said line, a switch associated with said line, are peater, means insaid switch for connectlng said line with said repeater, a secondswitch? a line connectingsaid repeater with said second switch, means insaid repeater responsive to said impulses for operating said secondswitch, and means for connecting in ductively said telephone line withsaid switch line after the secondswitch is operated, releasin devices insaid second switch and in said rst switch and circuits for operating thesame controlled from said repeater in response to said impulse'sendingmeans.

- 40. In 'a telephone system, a telephone line, means forsendingimpulses over said line, av repeater, means for connecting said linewith said repeater, a switch, a line connecting said switch with saidrepeater and electromagnetic means in said repeater responsive to saidimpulses for operating sai switch, and means for connecting inductivelysaid telephone line with said switch line after the switch is operated,releasing mechanisms in said switch and in said second means andcircuits for operating the said mechanisms from said repeater inresponse to said impulse sending means.

41. In a telephone system, a telephone line, means forsending impulsesover said line, a switch associated with said line, a repeater, means insaid switch for connecting said line with said repeater, a secondswitch, a line connecting said repeater with said second switch,electromagnetic means in saidrepeater responsive to said impulses foroperat'ing said secondswitch, and means for connecting inductively saidtelephone line with Si 11d switch line after the second switch isoperated, releasing devices in said second switch and in said firstswitch and circuits for operating the same controlled from saidrepeater:

in response to said impulse sending means.

42. In a telephone system, a telephone line,

means for sending impulses over said line, a

repeater, means for connecting said line with said repeater, a switch, aline connect-. ing said switch with said repeater, *and means in saidrepeater responsive to said impulses for operating said switch, and

progressively movable means for connectinginductively said telephoneline with said switch llne after the switch is operated, re-

leasing .mechanism in said switch and insaid second means and circuitsfor operating the said mechanisms from said repeater in response to saidimpulse sending means.

43. In a telephone system, a telephone line, means for sending impulsesover said line, a switch associated with said line, a repeater, means insaid switch for connecting said line with said repeater, a secondswitch, a

line connecting said repeater with said secand circuits for operatingthe same controlled from'said repeater in response to said impulsesending means.

4 1. In a' t lephone system, a telephone line, means for sendingimpulses over said line, a repeater, means for connecting said line withsaid repeater, a switch,- a line connecting said switch with saidrepeatenmeans' in said repeater responsive to said impulses foroperating said switch, and vmeans for connecting inductively saidtelephone line with said "switch .line after the switch is operated,releasing mechanism in said switch, releasing mechanism 'in said secondmeans, a first release circuit for operating d' said first releasingmechanism,-a second release circuit for operating said second releasingmechanism, said release circuits controlled from said repeater inresponse to said impulse sending means. v

45. In a telephone system, a telephone line, means for sending impulsesover said line,-a switch associated with-said line, a. repeater, meansin saidswitch for connecting said line with said repeater,.a secondswitch,

a line connecting said repeater with said sec- 0nd switch, means in saidrepeater responsive to said impulses for operating said second switch,and means for Connecting inductively said telephone line with saidswitch line after the second switch is operated, a releasing device insaid second switch, a releasing device in said first switch, a firstrelease circuit for controlling said first. re-

leasing device, a second release circuit for controlling said secondreleasing device, both of said releasing devices being controlled fromthe "repeater responsive to sa1d impulse sending means.

releasing mechanism in said second means,

a release circuit'for operating said first releasing mechanism a secondrelease circuit for operating said second releasing mechanism, saidrelease circuits controlled from said repeater in response to saidimpulse sending means.

47. In a telephone system, a telephone line, means for sending impulsesover said line,'a switch associated with said line, a repeater, means insaid switch for connecting said line with said repeater, a secondswitch, aline connecting said repeater with said second switch,electromagnetic means in said repeater responsive to said impulses foroperating said second switch, and means for connecting inductivelysaidtelephone line with said switch line after the second switch isoperated, a releasing device in said second switch, a releasing devicein said first switch, a first release circuit for controlling said firstreleasing device, a second release circuit for controlling said secondreleasing device, both of said releasing devices being controlled fromthe repeater responsive to said impulse sending means.

48. In a telephone system, a telephone line, means for sending impulsesover said line, a repeater, means for connecting said line with saidrepeater, a switch, a line connecting said switch with said repeater,progressively movable means in said repeater responsive to said impulsesfor operating said switch, and means for connecting inductively saidtelephone line with said switch line after the switch is operated,releasing mechanism in said switch, releasing mechanism in said secondmeans, a first release circuit foropcrating said first releasingmechanism, a second release circuit for operating said second releasingmechanism, said release circuits controlled from said repeater inresponse to said impulse sending means.

49. In a telephone system, a telephone line, means for sending impulsesover said line, a switch associated with said line, a repeater, means insaid switch for connecting said line with said repeater, a secondswitch, a line connecting said repeater with said second switch, meansin said repeater responsive to said impulses for operating said secondswitch, and progressively movable means for connecting inductively saidtelephone line with said switch. line after the second switch isoperated, a releasing device in said second switch, a releasing devicein said first switch, a first release circuit forcontrolling said firstreleasing device,- a second release circuit for controlling said secondreleasing device. both of said releasing devices being controlled fromthe repeater responsive to said impulse sending means.

50. An automatic telephone system comprising a plurality ofelectrically-propelled st-ep-by-step switches, a repeater, a callingsubscribers line temporarily connected with a called subscribers linethrough the medium of said switches, all except one of said switcheshaving line-relays temporarily disconnected from the line-conductorswith which they are normally connected, and said repeater apparatus,like one of said switches, having a pair of line-relays which remainbridged across the talking-circuit temporarily established between thetwo subscribers stations, said repeater line relays being controlled bythe calling subscriber to repeat impulses to the line relays of saidswitches during the establishment of the connection. I

51. An automatic telephone system comprising selectors, connectors, arepeater, a calling subscribers line temporarily connected with a calledsubscribers line through the medium of said selectors and connectors,said selector or selectors having linerelays temporarily disconnectedfrom the line-conductorstwith which they a-re nor-' mally connected, butsaid connector and repeater apparatus each having a pair of line-relayswhich remain bridged across the talking circuit temporarily establishedbetween the two subscribers stations, said repeater line relays beingcontrolled by the call-. in subscriber to repeat impulses to the linerel ays of the said selectors and-connector during the establishment ofthe connection. Signed by me at Chicago, Cook county, Illinois, this16th day of July, 1906. I

, JOHN ERI-CKSON/ Witnesses:

ROY'C. GIFFORD, EDwARoD. Farms.

